The invention relates to an exhaust gas filter, and more especially, to a soot filter for a diesel engine, having a filter body disposed in a housing through which the exhaust gases pass to be cleaned, and having an inlet duct and an outlet duct.
An exhaust gas filter of this type is described in German Offenlegungsschrift 38 18 281, for example. Such a filter is particularly advantageously used for the removal of soot and substances similar to soot from an internal combustion engine, especially a diesel engine.
Further areas of application are combustion installations in private, industrial or in public premises.
A filter body consisting of one or more compression moulded sintered products having high temperature stability can be used with particular advantage as a filter body. Such a filter body possesses high efficiency with simultaneously high thermal conductivity, with even catalytic effects partly occurring. This is the case especially if the filter body is coated with catalytically effective materials, such as, for example, platinum, rhodium, vanadium and the like.
A disadvantage of the known exhaust gas filters is that the gas back pressure in the filter can vary greatly as a function of the filter loading. Therefore, corresponding fluctuations in efficiency also result, in particular, in the filtration efficiency of impurities. Thus, for example, with an unloaded or only slightly loaded filter, i.e. with a new or cleaned filter, only a relatively small back pressure is sound, as a result of which the flow through the filter body is relatively fast. In contrast, if the filter is already heavily loaded, the gas back pressure is higher. This means that a correspondingly high resistance has to be overcome before there is a flow through the filter body, under which the engine rating, inter alia, suffers with the use of the exhaust gas filter in an internal combustion engine.
Therefore the object of the present invention is to create an exhaust gas filter of the type mentioned at the beginning, with which the above-mentioned disadvantages are avoided, and its efficiency in particular becomes more uniform and is improved.